Last year I got an F-50 in bubinga and wicker, and was in the market for a case of some kind. I did a lot of research into this. Here's what I was able to figure out:
If you need a REAL ATA spec case, you're going to spend a lot of money - easily over $300. But these are the real deal and can handle just about anything you need - you can travel anywhere and on anything and not worry. I'm sure you know the good names out there - Anvil, Calzone, Rock Hard etc. You have to call them and have the case custom built in most instances. For me, price was a concern, and in the final analysis I felt I didn't need that level of protection.
However, the slip cover was definitely not enough. I'm basically a weekend warrior and the amp always travels in the back of my Jeep, so all I really needed was something to put it in to prevent it from getting dinged up every time I load in/out. I ended up going with one of the case companies on E-Bay.
In researching the various E-Bay case companies (and I basically called every single one of them except the ones selling cases for more than $200), I was able to figure out it's all one company operating under different e-bay names. I ended up ordering a pretty basic case, but upgraded with butterfly latches, dolly wheels and interior foam. (Note if you don't specifically order the foam as an add-on, they come carpet lined). Including shipping and handling it cost me about $160 I think. It came within a week of placing my bid.
I'm happy with it. It's not cheesy looking and it does what I need, which is to say it provides basic protection against getting dinged. It would definitely not survive airline baggage handling, but I didn't need that. If price is an issue for you, and you don't need full-bore ATA protection, this is not a bad way to go. If I had it to do over I would try and get the bigger wheels, because the ones it came with are small.
That's my $0.02. Feel free to PM me if you want the specifics on who I ordered from, the exact cost and options etc. - I'll be glad to give you the info.